The present invention relates in general to an improvement in cover design for any machine having a horizontal rotor access to which is gained by removal of the cover and, more particularly, to an improved rotary knife cutter provided with a roll-off cover which may be readily translated to facilitate access to the cutter rotor for cleaning and maintenance.
Rotary knife cutters find very diversified application in industry for producing geometrically shaped particle sizes of any material that can be reduced by cutting or shearing action. One particular use of rotary knife cutter is for precise shearing of plastic film scrap such as pieces of polyethylene, polypropylene, or polyester films as thin as 1/2 mil and as heavy as 10 mil. It is customary in industry to recycle scrap plastic film that comes from trimming the edges of the rolls to provide a uniform edge on the film being manufactured, or from film that is defective in that it is off-spec in thickness or has impurities or holes. Typically, this scrap is passed through the rotary knife cutter and cut into fine pieces particles which are then mixed with virgin pellets, remelted and extruded to produce new film.
During the manufacturing process, it is often necessary to open the rotary knife cutter and clean any film particles that may have accumulated in cracks or crevices within the working chamber of the cutter housing prior to changing plastic composition or color to prevent contamination of the new batch when recycling the scrap material. Therefore, it is highly advantageous to manufacturers to have a method of very quickly opening the top of the rotary cutter housing to gain access to the rotary cutting knife for cleaning purposes. It is the present customary practice in the industry to provide rotary knife cutters which have covers hinged to the housing so that they may be lifted with a hydraulic cylinder, or which are merely bolted to the housing and removed by lifting with an overhead hoist after unbolting from the machine base. Unfortunately, such a process can be laborious and timeconsuming in that in commonly takes two men from one to six hours, depending upon the machine design and location, to open a prior art rotary knife cutter for cleaning or service.